Difference between answer and reply

Answer a spoken or written reply or response to a question, request, letter, etc.
Reply an answer or response in words or writing

One is explained by the other, lol.

The thesaurus says this: 1. an answer is something said, written, or done in return; a reply is an answer that satisfies a detail in a question
2. reply is generally used when the answer is understood to be verbal - either written or oral; response, by contrast, has a more general application and may be used for a variety of reactions
3. respond suggests a quick reaction while reply implies a return commensurate with the original demand or question

There is no real difference, although to some of us native speakers of English "reply" may seem more formal than "answer."

Here are the definitions, from the American Heritage Dictionary:

answer A spoken or written reply.

reply An answer in speech or writing.

However, "answer" can also mean a definitive response in a way that "reply" cannot. You never hear of a "question and reply" session.

What is 22? The answer is 4.

The teacher asked "what is 22?"
Billy answered "Four." [He gave the correct solution to the problem]
Billy replied "six!" [He responded to the teacher's question, but the solution was incorrect.]

I'll reply by just saying that I can't answer your question.

In most contexts the words are synonyms. From the American Heritage:

<blockquote>Quote
<hr>SYNONYMS: answer, respond, reply, retort These verbs relate to action taken in return to a stimulus. Answer, respond, and reply, the most general, all mean to speak, write, or act in response: Please answer my question. Did you expect the President to respond personally to your letter? The opposing team scored three runs; the home team replied with two of their own. Respond also denotes a reaction, either voluntary (A bystander responded to the victim's need for help) or involuntary (She responded in spite of herself to the antics of the puppy). To retort is to answer verbally in a quick, caustic, or witty manner: She won the debate by retorting sharply to her opponent's questions. See also synonyms at satisfy.<hr></blockquote>

But #3's correct, of course, that "answer" has a number of distinct meanings not all of which are related to the act of "replying." See the full defintion of the word "answer."

In this example:

A: Can you tell me how to get to the railway station?
B: I'm sorry, I've no idea, I don't live here.

I think B's response is a reply, but not an answer. An answer means A finds out where the station is.

I would say answer has a wider range of meanings than reply, it can also mean a solution to a problem, a match to a description.

Do you think that you might look for an answer to a problem but you wouldn't reply to a problem? You can answer a question, ie 2+2=4. but you can reply to a statement which begs no answer? Other than #4, I think we are all on the same page here.

Thanks for your replies :) They were quite complicated for me but they are useful :)